Method of and means for operating boilers of certain types



Sept. 21, 1937. T. E, MURRAY, JR 2,093,686

METHOD oF AND MEANS FOR-OPERATING BOILERS OF CERiAIN TYPES Filed Oct. 27, 1936 /OMA5EMRAVL k v BY I fl V I I ATTORNEYS l L t re n er 21," 193? 10 or; difllcr ltur-te Pmalntainllsucli" eirtens'ichls ",61 "the r I considerable length whichifis desire I sehemes'whavebee compllshlngkithisw isir larse bm eccontinuation or tl'ieetore illustrates Iembbdimentsj oi" the lhver'ition;

Fig.2 is affront elevation 01,8. per-min 'of the same; Flg. 3wis a horizontal SOtlOIIIthfO'llBh .oneef the I ig. 2, illustrating 9. modlflcatiomr t The pboilenwallmf Fig. 1 1 s :mhdehpu on 'm {shell l0, an iouter 1 pt plesti such as 1 a. heat insulating coetifijgi l bricks I 2; end 2% or ether: tameam inner facegthat islthe Iace'exDesed tb aliningmadeupottubularunits eachcombrislx'i'z" a tube I; with pins ernprblections 1H at 'di'ameh terial; and tire that; while constituting in efl'ect I an approxi-f mately ,coritinueus {metal welL theyjm-e sum-i ciently separatedto evoid actual I I I permitot their. separate weldliiztcthe with; eutinducing' in them suchl internal stresses as i would weaken their resistance .to oxidatlenend I atures contemplated. E'I'hls isto fit them-tor, the severest usage,-as inrthe walls 01' boiler furnaces "heated by pulverized or other fuel burned in myself @February 29, 1936, 1 ma euesmbe i 'u'nit' walls; in

t I time; as they burn;OIL-f1: The jaccempanfihg appll said application; uccomnenyi i's dra in I w r r Fi 1- Is e "horizontal sectlon' or a hollerlwallf 68421011 3 referred to ithe spacing and jsize fjof the r projections omeech tube ai'e determln'ed' li arder" contact lend to burning ofl'wat the ends under the lilghtempersubsc nuauy or; epprexlmetely-ljeon 'iilete "metiil .e wall. In practice it has beenfoundximposclble bduhtred lnf-hioderhfhigh tempe turemsmna A pm? pms mm mmn" t maintain the ori ina 1 ai ou hey? the rlcally opposite points c lproject'lxig mwme I t i i e m wo lsr mshimw ea 139118? lirrtieqes' it is desirable to have thefiprw Jbti s xtehdi g e ond this balanced point.

irrg aklenger life i' ricler" theedr ditlon's enceuirtered ss r thb zhii su ex e m n m I I fadditio'rlel adver tege or r qmnngi lgss" frequet'xt rebeirs orreplacements; 1 40 Acf cqrdlrlg ttg' M85513- ehd 4; the. tube l3 has 'tlieextensiohs' I l in; the fbrm oftsmalltubeseachf I welded by a, resistance weld l5 t6 the] main tube prqjectlpn may be 9. solid pm except for a 1101: 45

loweflits outer end. The outer endbtgthegpin W thin the'bcre of theYpin- H. The end piece l8 of-more highly reslsta'nt material than 50 the body of the pin 14. For example, the latter maybe 01 ordinarylow, carbon steel similar to I thet of theboile'r tube II and the end. piece of s'tainlese or other ,nickel chrome steel alloy. when the flrstend piece I! burns nearly 01!, the 5 pqsed tofinitiellyfapply"eiperrriiihent. 5 I

stub of it can beremoved and replaced by a new whole one, restoring the pin to its original length.

The extent of the end piece I6 should be sufficient to permit the necessary manipulation, but

no greater. It may be fastened to the end of the pin by welding or in any other way.

Fig. 5 shows a solid pin I 4* with an end piece l6 having a flange Il fitting around the end of the pin. This is used in the same way as the ar- 10 rangement of Figs. 3 and 4. r It is not essential to have theend portion separate from the body portion oi the projections. With modern methods of welding, and particularly with portable welders, it-is'possible to add 16 metal at the ends of the projections whether such ends be in the form of replaceable caps or blocks, or be integral originally.

For example, in Fig. 7 the tubes 13 are provided with pins H! which are initiallyintegral'irom 20 end to end. When they burn off their lengths may be shortened, for example, along the irregular' dotted line l9. After this burning awayhas become 'suflicient to make a fairly. wide opening between the ends of the pins that originally spanned the space between the two tubes, the flames have a better access to the ends and the backs of the pins than originally and the burn ing efl'ect is to that extent intensified. The wall back of the pins also loses its original substantially complete protection and burns awayat an increasing rate. The shortening of the pins also diminishesthe area of metal exposed to the fireand transmitting the heat thereof to the; tubes and to the water within the tubes causes a. diminution of the efliciency of the boilerand the speed with which it generates'steam.

I propose to keep these objectionabletendencies within substantially the original limit by adding metal to the endsof the pins from time totime so as to maintain their extension over .practically the entire width of the spaces between adjacent tubes. This may be done by squaring off the ends of the pins and welding previously shaped pieces thereon similar to the caps of Fig. 5, for example, or identical in diameter with the original pin, or by, depositing and building-up metal by means or known, types of electric arc welding machines. Such an operation is easily performed. It is'not essential to. maintain the extent or shape 01' the originalj'cross-section. In fact the ends may be enlarged and may even be united to the ends of the adiacent pins on the same tube or on the next tube in this repair operation without substantial objection.

In replacing the' burned away portions ot the projections they will generally be restored to substantially their original extent.v The restored made by those skilled in the art without departing from the invention as defined in the following claims.

What I claim is:

1. The method of operating a boiler or. the like having a wall comprising tubes spaced apart with projections extending into spaces between them and exposed to high temperatures, which method comprises adding metal to the outer end portions of said projections from time to time as they are burned oi! so as to maintain them of a determined extent.

time of said projections as they are burned off so as to maintain them of a. determined extent.

3. The method of operating a boiler or the like having a wall comprising tubes spaced apart with projections extending into spaces between .them and exposed to high temperatures, which method comprises extending said projections from time to time as they burn off so as to maintain them of an extent to substantially cover the width of: the space between the tubes and to provide an approximately continuous metal wall between the fire and the outer portion of the structure. i

v 4. A unit of the character described comprising a. tube for circulating a fluid and projections extending outward from said tube adapted to be exposed to high temperatures and to conduct heat to the tube and the fluid therein, said projections having outer end portions which are replaceable when burned oiT.

, 5. A unit-for use in boiler furnace walls comprising a tube having along diametrically opposite lines a series of small closely spaced projections extending outward therefrom, said projections having end pieces ,which are separate from the bodiesof the projections and are replaceable when burned oif.

6. The unit of claim 4, said outer end portions beingof material more resistant to oxidation at high temperatures than the body portion 0! the projections.

7. The unit or claim 4, the body portion and the end portion of the projections fitting one within the other.

8. The unit 01' claim 4, the body portion and the end portion of the projections being welded together. v

9. A unit of the characterv described comprising a tube for circulating a fluid andprojections extending outward from the tube adapted to' be exposed to high temperatures and to conduct heat to the tube and the fluid therein, said projections being hollow and having separate outer end portions fitting within the hollow space in the projections. I 1

10. A unit oi the character described comprising a tube for circulating a fluid and 'a series of small closely' spaced projections extending outward from the tube along diametrically opposite lines adapted to be exposed to high temperatures and to conduct heat to the'tube and the fluid therein, said projections being hollow.

. THOMAS MURRAY, JR.' 

